Nephropathy is a disease that typically develops over a prolonged period (e.g., 10-15 years) during which time the ability of the kidneys to properly function diminishes. Once the disease has progressed to end-stage renal disease (ESRD), a kidney transplant or dialysis is the only treatment option. The disease is caused, for example, by immune disorders (e.g. IgA nephropathy) or diabetes (e.g. diabetic nephropathy). In either case, nephropathy is characterized by the trapping of protein deposits, such as, the protein immunoglobulin A (IgA), inside glomerular capillaries of the kidney. These glomerular capillaries serve as the kidney's filtration system to filter waste and water from the blood. The protein deposits prevent the glomerular capillaries from properly filtering the blood resulting in high protein levels in the urine.
Once the glomerular capillaries are damaged, they cannot be repaired. Thus, treatment of nephropathy typically involves slowing the progression of the disease rather than curing it. Treatment consists of, for example, administration of therapeutics, such as angiotensin converting enzyme (ACE) inhibitors which reduce urine protein levels. A solution of the therapeutic can be delivered to the kidneys systemically or locally.
Prior to delivery of the therapeutic to the desired tissue, the therapeutic must be sterilized. There are many techniques for carrying out sterilization including chemical treatment, heat treatment, filtration, irradiation, or other methods. Since sterilization methods have the potential to affect properties of the therapeutic solution, factors such as the type of therapeutic, properties of the therapeutic solution and the particular use of the therapeutic in the organism must be considered when selecting the sterilization method.
In addition to the type of therapeutic and its use, a desired sterility level must be considered when selecting a sterilization method. The required sterility assurance level (SAL) for a product is dependent on the intended use of the product. SAL refers to the probability of a viable microorganism being present on a product unit after sterilization. For medical devices in particular, the level of sterility for a Class I device as per United States Food and Drug administration (FDA) classifications, which presents minimal risk of harm to the user and are simpler than Class II and Class III devices, will be different than the level required for Class III devices which are characterized by the FDA as devices that support or sustain human live, are of substantial importance in preventing impairment of human health, or which present a potential, unreasonable risk of illness or injury.